Leukotriene (LT) A 4 hydrolase (E.C. 3.3.2.6) is a Zn-containing metalloenzyme classified as a cytosolic epoxide hydrolase. It catalyzes the conversion of LTA4 to LTB4, a potent pro-inflammatory agent. The crux of this investigation is to understand the nature and mechanism of small molecule inhibition of the hydrolase activity of the LTA 4 enzyme with the objective to facilitate the design and development of pharmaceuticals to treat inflammation. Although aminopepidase activity was also found with this protein, its "natural" substrate has not been identified.